2-isopropylidene-4-cyclopenten-1,3-dione

5-Isopropyliden-4-hydroxy-2-cyclopentenon

6,6-二甲基-5-亚甲基-1,3-环戊二烯

3-hydroxy-2-propan-2-ylcyclopent-2-en-1-one

2-phenylselanyl-2-propan-2-ylcyclopentane-1,3-dione